Mapping with derived entries

[osamimi]

I am evaluating pkl for an application. I would have a schema definition that is provided by me:

class Param {
  val: Int | Float
  signed: Boolean = true
}

class TopConfig {
    module_name : String
    params : Mapping<String, Param>
   // etc
}

and an actual config written by the user of the framework:

import "schema.pkl"

k = new schema.TopConfig {
  module_name = "parent"

  params {
    ["inw"] { val = iniw.val + inqw.val }
    ["iniw"] { val = 1 }
    ["inqw"] { val = 23 }
  }
}

So essentially I have a type object called Parameter with defined properties, and I want the user to be able to define an arbitrary number of Parameters where some Parameters depend on other Parameters.

Using a Mapping to do this is not working:

What should I be doing instead?

[HT154]

Mapping entry access happens via subscripting, so you would need to do this:

params {
  ["inw"] { val = this["iniw"].val + this["inqw"].val }
  // ...
}